The frequency of interstrand cross-links in DNA following reaction of cis-diamminedichloroplatinum(II) with cells in culture or DNA in vitro: stability of DNA cross-links and their repair.

DNA that had been reacted in vitro with cis-diamminedichloroplatinum(II) (cisplatin) had the same frequency of interstrand cross-linking (namely, approx. 1 cross-link per 150 platinum reaction) as that found in the DNA isolated from cells in culture immediately after their treatment with cisplatin. Incubation of both the in vitro and in vivo platinum-reacted DNA in sodium citrate buffer for 24 h at 37 degrees C resulted in up to a 5-fold increase in cross-link frequency.